The analog of the “Line for continuous applying the protective metal coating on the steel lengthy products” is the line for applying the protective metal coating on the tube surface, which includes transporting mechanisms, heating tools, tube bending tools, setting driving housing, tank for the melt and mechanisms for tube delivery and straightening with cooling tools. Bending tool is made in a shape of bent perforated tube of corrosion resistant material, its bent part being placed lower in the tank than melt surface (RU No 22048594).
The disadvantage of this line is the necessity to bend the tube for plunging it into the melt.
The closest analog of the “Line for continuous applying the protective metal coating on the steel lengthy products” is the line for lengthy products hot metallization including tanks placed in sequence and coaxial for fluxing and metallization, plungers with directing rolls placed in them, calibrating device with passage of square cross section, cooling camera with sprayer device and take-in-out mechanism. Calibrating device is made in a shape of fiber (filier) placed inside of the metallization tank with the lengthwise movement possibility. The line is equipped with functional elements speed and tension stabilizer placed in front of the tank, and diverting device placed between plungers and made in a shape of lengthwise vertically stand flat frame with cross dowels having vertical projections in the lower part of the frame and rollers placed in the upper part of the frame with rolling and slipping possibility (SU No 1568562).
For applying the metal coating by means of this line the lengthy product is undergone the bending to plunge it into the tank with melt and following straightening, which complicates line construction and the process of applying the coating.
The analog of the invention “Line for continuous applying the protective metal coating on the steel lengthy products” is the device according to the patent application RU No 998120056. The device comprises the vessel for the tank with melt coating metal, the upper surface of the tank having the opening for bend passage is connected with said vessel, placed under said upper tank surface, and provided with means for inserting the metal band. The device has also the tool for transporting the continuous metal band through said opening and through the tank. This device comprises the plug formed from the hardened metal coating and embracing band at the section run after said opening, while the plug is stationary relatively to the band and has the tool for preventing the tank melt metal flowing out trough said opening and providing the band transporting through the tank at the same time. Besides, there is a tool for cooling the metal coating placed inside said vessel run after said opening for the plug formation and plug fixing during applying the coating on the band, and tool for heating the melt metal tank at the section run after said plug.
Another analog is device for applying the protective coating on the lengthy metal products comprising the tank with heating elements and passage in the bottom of the tank, MGD-lock under the passage with outlet partially inserted into the tank trough the passage. MGD-lock is presented as two L-shaped magnetic circuits with two flat coil of single-phase winding placed at the vertical rods of the magnetic circuits (SU No 492759).
In this device the lengthy product is transported vertically into the tank with melt without bending. The disadvantage of this apparatus is its complication as a result of MGD-lock using.
The devices for applying the coating on the wire, band and so on, in which using of directing roll plunging the product into the melt and transporting it, are known (“Hot zincing guidance”, Moscow, “Metallurgy, 1975, p. 376; “Metal coatings of sheet and bar steel” Vitkin A. I., Taidle I. I., Moscow, “Metallurgy”, 1971, p. 496).
The disadvantages of the known lines and devices for applying the protective coatings are steel tanks having big volume and significant open melt surface square, which predetermines big power consumption to maintain set temperature of the melt. In particular, the contact of zinc melt with steel walls of the tank and with elements of immersion transporting devices provides iron dissolvent in the zinc and, as a result, shorts the equipment operating period and enlarges zinc consumption.
Using the steel tanks with immersion transporting device excludes the possibility of alloying the melt with aluminum. Ceramic tanks are resistant to the zinc melt alloyed with aluminum but they have a big volume in comparison to steel ones. This is the case because, unlike in the metal tanks where hitting is provided trough the walls, in the ceramic tank hitting is provided through the melt surface.
In the analog device for applying the metal coating on the steel band surface according to the patent application RU No 94041744 the product is entered vertically into the tank with melt through the passage in the bottom of the tank without changing the direction. The preventing of melt flowing out through the passage in the bottom of the tank is provided by means of electromagnetic forces. This force is proportional to the static pressure of the melt metal and opposite to it by the direction. The tank with melt is provided with extra tank for pre-melting, the volume of the tank for applying the coating being several times smaller than one of the pre-melting tank. The level of the melt in the tank for applying the coating is regulated by means of melt moving from the pre-melt tank to the tank for applying the coating. The pre-melting tank is placed aside under the tank for applying the coating. Electromagnetic pumps are provided for melt coating material circulation.
The closest analog of the offered device is the device for applying the metal coatings on the lengthy products comprising tank with the melt and camera for applying the coating (application of France No 7516981, class C23C3/14, 1975).
The camera for applying the coating in this device has input and output passages through which the product is transported while applying the coating is provided. The melt is transported from the tank into the camera for applying the coating by means of the pump. Filling the camera is provided in such a way that the melt level in the camera is set higher than level of input and output passages. The melt is easily flows out the camera into the tank, however the quantity of the melt returning to the camera is a bit more than one flowing out the input and output passages into the tank. It allows maintaining the melt level in the camera for applying the coating higher than one of input and output passages.
The disadvantage of this device is the fact that the melt supply from the tank into the camera is provided by means of immersion pump, which significantly decreases the safety characteristics imposed to the industrial equipment. The continuous melt circulation causes fast wearing of passages and melt contamination with materials from which the passages are made of, which causes deterioration of the coating formation and, therefore, the decrease of its quality.